Edgewise Group Research Articles

Incisor and profile alterations in extraction cases treated with standard Edgewise and pre-adjusted appliances: A controlled before-and-after study

Even though treatment of Class II malocclusion with premolar extractions and incisor retraction might affect incisor inclination and soft tissue profile, the effects of bracket prescription on this have not been thoroughly assessed. Fifty patients (mean age: 13.6 years; 34% male) receiving extraction-based treatment with either standard Edgewise or pre-adjusted appliances were included. Between-group differences in the incisor inclination assessed with lateral cephalograms were analyzed statistically with linear/logistic regression at 5%. Treatment-induced changes included retroclination of the upper/lower incisors (-3.0° and -2.0°, respectively), retraction of the upper/lower incisors (-3.4 mm and -1.5 mm, respectively), retraction of the upper/lower lip (-2.1 mm and -2.0 mm, respectively), and enlargement of the nasolabial angle (+1.6°). Analysis of the data adjusting for confounders indicated that the pre-adjusted group, after treatment, had larger inclination of the upper or lower incisors (+3.2° and +4.5°, respectively), more prominent upper incisors relative to the facial plane (+1.3 mm), and smaller interincisal angle (-7.3 or -7.7°). Post-treatment upper incisor inclination fell within the cephalometric norm significantly more in the pre-adjusted than in the standard Edgewise group (odds ratio 4.3; 95% confidence interval 1.1-16.6). No differences were found in lower incisor prominence, upper/lower lip prominence, or nasolabial angle. Pre-adjusted appliances were associated with increased inclination of the upper and lower incisors, with more prominent upper incisors, and with more acute interincisal angle after retraction compared with standard Edgewise appliances. However, such differences did not translate in greater retraction of the upper/lower lips and greater nasolabial angle.

The effect of fixed orthodontic treatment with Edgewise and Straightwire techniques on white spot lesions incidence and accumulation of Streptococcus mutans bacteria

Background: Fixed orthodontic appliances, such as Edgewise and Straightwire techniques, can increase the amount of plaque retention containing Streptococcus mutans (S. mutans), which can lead to white spot lesions. Purpose: The aim of this study is to analyse the correlation of fixed orthodontic treatment with Edgewise and Straightwire techniques on the incidence of white spot lesions and accumulation of S. mutans. Methods: The samples consisted of three groups: control group (n=8), Edgewise technique group, and Straightwire technique group. We observed the samples at the sixth month and eighth month of the treatment, after the installation of the fixed orthodontic appliances. The observation of white spot lesions with caries detector was applied in all regions. Bacterial swabs were acquired in the lateral incisor region, then a bacterial culture procedure was carried out on selective media of S. mutans, and then a bacterial count was performed. The data was analysed using two-way ANOVA, the post-hoc least square differences test, and the Pearson’s correlation test. Results: The number of white spot lesions in the Edgewise group was higher than in the Straightwire group in the sixth and eighth month of treatment with insignificant difference (p>0.05). The number of S. mutans bacteria increased in all groups, but there were no significant differences (p>0.05). There was no significant relationship between the number of white spot lesions with the accumulation of S. mutans between groups (p>0.05). Conclusion: The Edgewise and Straightwire techniques increase the incidence of white spot lesions but accumulation of S. mutans with the incidence of white spot lesions has no relationship.

Evaluation of treatment changes produced by different orthodontic treatment modalities using Peer Assessment Rating (PAR) index

Background: The assessment of treatment outcome has been an important facet of the orthodontic specialty for several decades. Generally, the orthodontic outcome is graded subjectively or by some objective method of evaluation in the clinical setting or of the study groups. The individual grading of one's own treatment results can be a self-educating exercise to improve the quality of care. Unfortunately, the variation in the criteria used by different orthodontists makes it difficult to compare the results Materials and Methods: A sample of 150 treated cases was divided into three groups as follows: Group A (n = 50) treated with edgewise mechanotherapy, Group B (n = 50) treated with light wire mechanotherapy, and Group C (n = 50) treated with functional appliance therapy. All the three groups were analyzed using Peer Assessment Rating (PAR) index. The degree of improvement in each case was categorized into three as worse-no improvement, improved, and greatly improved. Statistical analysis used: Chi-square test was used for comparison within groups and one-way analysis of variance (ANOVA) for comparing treatment improvement between groups. Results: All the three groups showed significant overall improvement after treatment. However, the patients in edgewise group demonstrated greater degree of overall improvement in comparison to the rest. Conclusions: The PAR index appeared to be sensitive enough to determine the difference in outcome between the techniques used in this study.

The effects of a newly designed twin-slot bracket on severely malpositioned teeth--a typodont experimental study

The aims of this study were to design a twin-slot bracket featuring two horizontal slots and to examine its efficiency in tooth displacement. Based on the structure of a traditional edgewise bracket, an additional slot was added to a twin-slot bracket and the prototype products were fabricated for the typodont experiments. The orthodontic correction of malpositioned canines was conducted on a typodont to examine the efficiency of the twin-slot bracket in tooth displacement compared with a single-slot edgewise bracket. Three modalities of tooth movement requiring a heavy force moment, namely, axial rotation, mesiodistal tipping, and bodily translation, were conducted. The canine positions before and after simulation were measured and the changes identified. Statistical analysis was undertaken using a t-test to determine the significance of the differences in canine repositioning between the two bracket types. The results showed that in the twin-slot bracket group, the treatment changes in the canine position by derotation and uprighting were 40 +/- 3 and 25 +/- 2 degrees, respectively, compared with 20 +/- 5 and 10 +/- 2 degrees in the edgewise group (P < 0.01). When retracted into an extraction space with an initial 10 degrees of mesial tip, the mesiodistal angulation of the canines in the twin-slot bracket group remained unchanged while in the edgewise group the canines became distally tipped by 5 +/- 2 degrees (P < 0.01). The twin-slot bracket significantly increased the bracket width without reducing the interbracket span and therefore can generate increased force moments within the bracket, leading to an improved manipulation in tooth repositioning.

The relationship between hard and soft tissue changes following treatment of Class II division 1 malocclusions using Edgewise and Frankel appliance techniques

Lateral-skull radiographs were used to examine the hard and soft tissue changes following overjet reduction in 62 children with moderately severe Class II division 1 malocclusions. Thirty-two patients were treated by non-extraction methods using Fränkel appliances, and the remainder by a standard Edgewise technique involving extractions and extra-oral traction. The relationships between changes in upper and lower lip positions, naso-labial angle, and labiomental fold with those in the underlying dento-skeletal elements were examined. The ratio between movement of the upper lip prominence and upper incisor crown was also calculated. Finally, the patterns of correlation between the two groups were compared. Both Spearman and partial correlations were calculated. The latter were used in an attempt to separate the true treatment effects from those of growth. This reduced the number of significant correlations considerably, 'sharpening' the results so that expected levels of agreement were enhanced, whereas spurious results were reduced. Few correlations reached a level of r = 0.7 or above. Incisor retraction was correlated with upper lip movement at this level only in the Edgewise group. No correlations were found between changes in naso-labial angle, labio-mental fold, and their underlying hard tissues. The Spearman correlations largely agreed with those of other authors, indicating that most of their apparently concordant hard and soft tissue movement was due to growth rather than appliance therapy. The use of ratios to compare upper lip and maxillary incisor retraction was not relevant in the functional appliance group because the average lip change was very small. It is concluded that the relationship between hard and soft tissue movement is too complex to be examined in a relatively simplistic way.

A comparison of Class II treatment changes noted with the light wire, edgewise, and Fränkel appliances

The purpose of this study was to determine if selected cephalometric changes noted in groups of growing patients with Class II, Division 1 malocclusions treated with the Fränkel function regulator (FR-2), the edgewise technique, and the light-wire (Begg) mechanism were different and characteristic of a specific technique. To this end, the changes in the SNA, SNB, N-S-Gn, and the SN-GoGn angles, face height (N-M), the anterior movement of pogonion, and the annualized mandibular growth increment (AR-Gn) in a group of patients treated with the FR-2 were compared to the changes noted in similar groups of patients treated by the edgewise technique and the light-wire mechanism. The methods used to compare the groups were an analysis of variance and a discriminant analysis. A reduction in the SNA angle was observed in all groups. It was −0.37 ° with light wire treatment, −0.60 ° with Fränkel appliance use, and −1.47 ° with edgewise therapy. The SNB angle increased in all three groups, ranging from 0.29 ° in the edgewise group to 0.56 ° in the Fränkel group. In the light-wire group it was 0.34 °. The N-S-Gn angle in the Fränkel group remained essentially the same (0.06 °), while in the light-wire and edgewise groups it increased 0.81 ° and 0.82 °. The SN-GoGn angle opened slightly in all groups, ranging from a low of 0.46 ° with Fränkel therapy to 0.58 ° with edgewise treatment to 1.25 ° with the use of the light-wire appliance. Face height (N-M) increased in all groups: 5.86 mm in the Fränkel patients, 6.12 mm in the light-wire group, and 7.38 mm in the edgewise group. Pogonion moved anteriorly 1.62 mm in the light-wire group, 2.14 mm in the edgewise group, and 2.60 mm in the patients treated with the Fränkel appliance. Finally, the annualized increase in mandibular length (Ar-Gn) was similar for all three groups: 2.70 mm (edgewise), 2.90 mm (light-wire), and 3.10 (Fränkel). There were no statistically significant differences in any of the variables when the changes occurring with all three techniques were compared.

The Begg light-wire treatment: A comparative study

A clinical and cephalometric study was conducted to compare the treatment results achieved with the Begg light-wire appliance with those obtained with the edgewise mechanism supported by cervical anchorage. There were thirty-one patients were in the Begg group and twenty in the edgewise group. The following conclusions were reached: 1. 1. The mandibular plane angle did not increase more in the light-wire group. 2. 2. The occlusal plane angle increased an average of 5.7 degrees in the light-wire patients and 4.3 degrees in the edgewise patients. 3. 3. The maxillary incisors were retracted an average of 0.6 mm more in the Begg group. They were not elongated any more than those in the edgewise group. 4. 4. The mandibular incisors were maintained well in accordance to the A-P line in both groups. 5. 5. There were considerably more arches and adjustments in the edgewise group. 6. 6. The treatment results achieved with the Begg method were at least as good as those obtained with the edgewise appliance.